Metalloporphyrins will be studied by the techniques common to physical inorganic chemistry. Reactions and properties often found in organometallic compounds will be sought and investigated. Particular attention will be paid to metal-metal interactions via direct metal-metal bonds or intermediate ligands such as oxo bridges. Iron systems will be examined by Mossbauer spectroscopy. Kinetic and equilibria studies will also be carried out of substitution and dimerization reactions involving metalloporphyrins.